Recoil amplifier for machine guns



Aug. 2, 1955 E. SAETTER-LASSEN 2,714,332

RECOIL AMPLIFIER FOR MACHINE GUNS Filed Sept. 21, 1950 zs 29 A INvEIv-rmg Er: k SA TTE' -LR SSEN 2,714,332 Patented Aug. 2, 1955 ancon. AMPLIFIER FOR MACHINE GUNS Erik Saetter-Lassen, Gentofte, near Copenhagen, Denmark Appiication September 21, 1950, Serial No. 185,936

Claims priority, application Denmark November 1, 1949 4 Claims. (Cl. 8914) The resent invention relates to a machine on having a barrel locked by bayonet lock to the breech block of the gun and exchangeable to the front, and a jacket open at top and fixed to the receiver of the gun, to which jacket is coupled a muzzle recoil amplifier which at the same time forms the forward sleeve bearing of the barrel.

The machine guns of this kind so far known suffer from the drawback that the recoil amplifier has either been hinged to the jacket and therefore has formed only a loose and insecure bearing for the barrel, or that the recoil amplifier has been firmly screwed into the forward, and in that case fully cylindrical part of the jacket, so that on account of the sloping position assumed by the barrel after release to the rear in order that it might be drawn rearwards out of the amplifier, so that the jacket has been able to support the barrel at top and bottom only over lengths that did not correspond to one another, whereby the barrel during firing might be exposed to harmful bending stresses.

In contradistinction the gun according to the invention is distinguished by the fact that the recoil amplifier is fixed by a bayonet lock to a strengthened forward part of the jacket in a manner identical to that in which the barrel is locked to the breech block, and further, the amplifier has a pipeshaped part extending to the rear and coupled to the barrel by a key projecting into a longitudinal keyway in the barrel, which part is provided with a handle by means of which the two parts thus coupled together may be turned and pulled forward to release them from the bayonet locks, so that the pipe and the recoil amplifier may be lifted up out of the jacket and a new barrel with recoil amplifier may be inserted by similar manipulations in the reverse order.

By this construction the barrel will be provided with a secure bearing at front and as a further result the handle will remain stationary during firing in contradistinction to previous practice when the handle had to be fitted to the recoiling barrel. The construction according to the invention entails the further advantage that the recoil amplifier is exchanged together with the barrel, so that it will be possible to clean the amplifier of fouling without interfering with the firing.

It will be expedient to provide the recoil amplifier forward of its bayonet lock lugs with a flanged socket which when the bayonet lock is locked will grip the front part of the open jacket and thereby prevent the side walls of o the jacket from being forced apart.

The invention is illustrated in the drawing in which Fig. 1 shows a horizontal, axial section through the forward part of a machine gun according to the invention, so, however, that the righthand part of the figure counting from line A-A shows a section on the line ll in Fig. 4,

Fig. 2 a section on line IIH in Fig. l, with bayonet lock closed,

Fig. 3 a section on line IIII1I in Fig. 1, with the bayonet lock turned to opening position,

Fig. 4 a section on line IVIV in Fig. 1, with the handle in a position corresponding to locked bayonet locks, and

Fig. 5 a section on line V--V in Fig. 1.

In all the figures 1t designates the barrel of the ma chine gun, 11 its jacket open at top, and 12 the recoil amplifier, the gas chamber 13, of which situated in front of the muzzle of the barrel is closed by a perforated disc 14, inserted in the bottom of a socket is, screwed to the amplifier and expediently constructed in one with a flash screen 16. By exchanging the perforated disc 14 by another disc with a larger or smaller central opening 17, the gas pressure in chamber 13 may be varied and the amplification of the recoil regulated. Behind the gas chamber the recoil amplifier extends to the rear as a pipeshaped bearing 12 forming a sleeve bearing for the forward part of the barrel, being itself resting in and connected with the forward part 11, of the jacket 11. In Fig. 1 the barrel is shown in its forward position.

The barrel is at its rear end bayonet locked to the breech block 32 of the gun, which as a recoiling part slides in the receiver 31 of the gun, to which receiver the rear of the jacket 11 is fixed.

The connection between the bearing sleeve 12 of the recoil amplifier and the reinforced forward part 11', of the jacket 11, is a bayonet lock of the same kind as the connection between the barrel and the breech block, part 12 being on its outer cylindrical surface provided with two opposing lugs 18, shaped as parts of an annular flange, to engage which the concave cylindrical bearing surface of part 11 for part 12 is provided with a corresponding annular keyway 19, and further, the bottom of the bearing has a longitudinal wide keyway 20, for the entry of one of the said lugs 13, leading from the front edge of the bearing and to the annular keyway, the other lug 18, will at the same time enter longitudinally through the opening at the top of the jacket. To secure still further the connection between parts 11 and 12 the latter is over part of its circumference provided with a flanged socket 21, by which when the bayonet lock is locked it grips the forward end of the reinforced part 11' of the jacket open at top.

In the embodiment shown the recoil amplifier 12, 12 is extended somewhat farther to the rear. part 12 of the amplifier may expediently have a slightly smaller external diameter than the forward part 12 and may be non-rotatably coupled to the barrel 10, by means of a lug 22, radially projecting from the inner wall of the part and engaging a longitudinal keyway 23, cut in the material of the barrel of the same length or preferably slightly longer than the maximum recoil of the barrel.

It is, however, a condition precedent to such rotatable coupling between the barrel and the recoil amplifier that the two bayonet locks, i. e. the barrel bayonet lock in the breech block and the amplifier bayonet lock in the jacket, are so adjusted in relation to one another that their opening will require the same angular turn of the barrel and the recoil amplifier. In that case the turning of the parts may be performed by a common handle 24, which may suitably be fitted to the recoil amplifier as this will entail the result that the handle remains stationary during firing and that the turnable parts when the bayonet locks have been locked may be secured against getting loose, for instance, by having the handle 24, mounted on the top of a short arm 25, radially projecting from the extension of the recoil amplifier 12 swivelled in the longitudinal direction of the gun on an axle 26, between a ball-locked service position and a ball-locked neutral position, the handle being provided with an arm 27, which when the handle after locking of the bayonet lock is turned to neutral position will engage a notch 28 in the jacket.

This rearward Out of regard to the dismantling of the coupled parts the abovementioned lug 22, is a screw-bolt which with threads extending all the way up to its head is inserted and screwed into a hole in the wall of part 12 or preferablyas shown in the righthand part of Pi g. l, where the screw-bolt is designated 29-screwed into the top of arm 26 and extending with its unthreaded part through the arm and projecting under it.

30 is a post fastened to one side of the jacket and curving in over the centre of the barrel to carry the foresight at so high a level that it will not interfere with the removal of the barrel.

As regards the embodiment shown the exchange of barrels is performed solely by means of the handle 24, and in the following manner: aVith the gun placed on a table in front of the operator with the barrel pointing to the left and the foresight post vertical, the gun is held in position with the left hand while the right hand grips the handle 24, and turns it to service position and then through the angle necessary for the opening of the bayonet lock around the axis of the barrel to a position above the latter whereupon it is pressed forward to release first the recoil amplifier and then the barrel from their bayonet locks. The two parts are then together lifted out of the jacket.

Normally the entire unit: barrel-recoil amplifier will be exchanged. If it should be desired to exchange only the barrel, the screw-bolt 29, with the lug 22, must be unscrewed so as to be released from the keyway 23, and the barrel may then be pulled back out of the pipeshaped recoil amplifier.

Replacement of the parts after exchange takes place in the reverse order.

Having thus described my invention, what I claim is:

1. A recoil amplifier for a machine gun, said machine gun comprising a receiver and a recoiling breech block slidably disposed in said receiver, a barrel having its rear portion bayonet locked in said breech block by rotation of said barrel through a predetermined angle and a jacket having a reinforced forward portion with a bayonet lock therein and secured at its rear to said receiver, said recoil amplifier comprising: releasable locking means connecting said recoil amplifier to said barrel which locking means permit the barrel to reciprocate longitudinally in regard to said amplifier but prevent the barrel from being turned with regard to said amplifier; and a bayonet locking portion engageable and disengageable with said reinforced forward portion of said jacket by rotation of said recoil amplifier through said predetermined angle.

2. A recoil amplifier according to claim 1, wherein said barrel has a longitudinal groove formed therein at its outer surface and wherein said recoil amplifier comprises an inner surface surrounding the forward end of barrel and a radially inwardly projecting lug which extends from said inner surface and engages said groove, said groove and said lug forming said releasable locking means.

3. A recoil amplifier according to claim 2, wherein said jacket is open at its top, and wherein said inwardly projecting lug consists of the end of a screw which engages said groove, said amplifier being provided with a reinforced portion in which said screw is threaded, said reinforced portion extending upwardly through said open top of said jacket.

4. A recoil amplifier according to claim 1, wherein said recoil amplifier is further provided with an annular outer collar having a rearwardly projecting flange which, when the recoil amplifier is assembled in the gun, surrounds and engages the front end of said jacket.

References Cited in the file of this patent UNITED STATES PATENTS 1,089,078 Rabba Mar. 3, 1914 1,234,575 Schneider July 24, 1917 FOREIGN PATENTS 16,252 Great Britain Aug. 25, 1904 

